Molecular simulation of hybrid polymer nanocomposites with organic nanodimers and inorganic nanorods: From structure and dynamics to viscosity

Polymer nanocomposites (PNCs) are cutting-edge materials that enhance polymer matrices with nanoparticles to achieve superior performance. The properties of these composites are significantly influenced by interactions at the nanoparticle-polymer interface. This study explores how inorganic nanorods (NRs) and various organic nanodimers (NDs)-differentiated by their interaction with the polymer and including Janus types-impact the structure, dynamics, and viscosity of PNCs. Through molecular simulations, we reveal how these nanoparticles interact within block copolymer and homopolymer matrices. Our findings show that ND-monomer interactions notably affect ND organization and improve barrier properties, while the structuring of NRs contributes to increased mechanical resistance. Furthermore, different PNCs provide a wide range of thickening behavior depending on the polymer matrix and the embedded nanoparticles. We observe increments of up to six times the melt's viscosity when both nanoparticles are introduced into copolymers. The viscosity of the systems is evaluated using a non-equilibrium method, the SLLOD algorithm, and the Green-Kubo relation to obtain both the shear-thinning curve and the zero-shear viscosity value. These results underscore the importance of nanoparticle interactions and configurations in determining PNC behavior, providing critical insights for advancing material design and functionality.